在like语句上联接SQL Server表 [英] Join SQL Server tables on a like statement

问题描述

我希望这不会重复.我检查了搜索结果，但似乎找不到明确的答案.

I am hoping this isn't a repeat. I've checked the searches and I can't seem to find a clear answer to this.

我有一个表，该表的主键设置为UniqueIdentifier.我还有另一个表，该表的varchar列基本上包含一个带有查询字符串的URL，该查询字符串包含来自我的第一个表的guid.

I have a table that has it's primary key set to be a UniqueIdentifier. I also have another table that has a varchar column that basically contains a url with a query string that contains guids from my first table.

所以我的2张桌子就像:

So my 2 tables are like:

状态表

StateID                                  StateName
EB06F84C-15B9-4397-98AD-4A63DA2A238E     Active

URLTable

URL
page.aspx?id=EB06F84C-15B9-4397-98AD-4A63DA2A238E

我想做的是将URLTable和StateTable连接在一起.StateID的值包含在URL表的URL中.我还没有真正弄清楚这个加入.我什至尝试只选择一个表并尝试按StateTable中的值进行过滤.我已经尝试做过这样的事情:

What I'm trying to do is join together URLTable and StateTable ON the value of StateID is contained in URL of URL table. I haven't really figured out the join. I've even tried just selecting the one table and tried to filter by the values in StateTable. I've tried doing something like this:

SELECT  *
FROM URLTable
WHERE     EXISTS
    (SELECT  *
     FROM  StateTable
     WHERE URL LIKE '%' + StateID + '%')

即使这样也不起作用，因为它表示我正在比较uniqueidentifier和varchar.

Even that doesn't work because it says I'm comparing uniqueidentifier and varchar.

有什么方法可以使用like命令联接2个表，并且like命令没有比较2个不兼容的变量?

Is there any way to join 2 tables using a like command and where the like command isn't comparing 2 incompatible variables?

谢谢！！

更新:让我添加一些我应该提到的其他内容.该查询用于构建分析报告.表格是CMS分析软件包的一部分...因此，更新或更改表格结构不是一种选择.

UPDATE: Let me add some additional things I should have mentioned. The query is for the purposes of building analytics reports. The tables are part of a CMS analytics package... so updating or changing the table structure is not an option.

第二，由于这些表正在捕获站点分析，因此流量非常大……因此，性能非常成问题.第三件事是，在我的示例中，我说了id =，但可能有多个值，例如id=guid&user=guid&date=date.

Secondly, these tables see a very high amount of traffic since they're capturing site analytics... so performance is very much an issue. The 3rd thing is that in my example, I said id= but there may be multiple values such as id=guid&user=guid&date=date.

更新2:我刚刚意识到的另一件事是，有时查询字符串中的破折号已从GUID中删除..有时没有..因此，除非我弄错了，否则我无法将子字符串转换为Uniqueidentifier.任何人都可以确认吗?叹气.我确实使用

UPDATE 2: One more thing I just realized to my horror is that sometimes the query string has the dashes removed from the GUID.. and sometimes not.. so unless I"m mistaken, I can't cast the substring to Uniqueidentifier. Can anyone confirm? sigh. I did get it to work using

REPLACE('-','',CONVERT(varchar(50), a.AutomationStateId))

但是现在我非常担心与此相关的性能问题，因为URL的表很大.但是，除非我无能为力，否则这可能就是野兽的天性.

but now I'm very much worried about performance issues with this since the URL's table is very large. This might be the nature of the beast, though, unless there's anything I can do.

推荐答案

将StateID转换为兼容类型，例如

Cast StateID to a compatible type, e.g.

WHERE URL LIKE '%' + CONVERT(varchar(50), StateID) + '%'

或

WHERE URL LIKE N'%' + CONVERT(nvarchar(50), StateID) + N'%'

如果URL为nvarchar(...)

if URL is nvarchar(...)

编辑

正如另一个答案中指出的那样，这可能会导致大型表的性能下降. 将LIKE与CONVERT结合使用将进行表扫描.对于小型表来说，这可能不是问题，但如果性能出现问题，则应考虑将URL分为两列.一列将包含"page.aspx?id ="，另一列将包含UNIQUEIDENTIFIER.这样，您的查询就可以更加轻松地优化.

As pointed out in another answer, this could result in poor performance on large tables. The LIKE combined with a CONVERT will result in a table scan. This may not be a problem for small tables, but you should consider splitting the URL into two columns if performance becomes a problem. One column would contain 'page.aspx?id=' and the other the UNIQUEIDENTIFIER. Your query could then be optimized much more easily.

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